I would say for the most part to stay away from Zulutrade. Most of their popular systems are less than 1 year old. The reason being, most Forex systems blow up after a year. That is not to say all of their systems are bad, but I am sure a year from now, you won't be seeing the same systems.
Zulu is also designed to not show what is happening to most traders like other tracking web sites. For example, on other sites they show user reviews and you can see when a signal provider blows up, and gets 1 star reviews from his customers.
Also, you get what you pay for, really good traders are not going to sell their signals on Zulu, since the compensation is so low.
Zulu is compensated by bucket shop Forex brokers because they are making money off its clients. This reminds me when the hedge funds paid Goldman to create some CDS and include the worst loans in them to sell since they were on the other side of the trade.